Work rest and method of forming the same



June 21, 1949. ZIMMERMANN 2,474,138

WORK REST AND METHOD OF FORMING THE SAME Filed Aug. 31, 1945 34 3E WIIQ 7,1,1: 3/ will IVIIII'I,

INVENTOR [was Zz'mmzrmalm nTroRr EYs Patented June 21, 1949 WORK BEST AND METHOD F- FORMING THE SAME ukas Z mmerma ir i s iair Mich- Application August: 31, 1945; Serial-Not 613,823

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st ndifirst and has. ion an; object, to, provide an improvedaworlme t; 13 1;, snppommgwqmpieces during he grindin operation.

One of the problems-incident to the m n fi re of; artiolesby. eenterless. grinding. has been to provide worn.- rests. with tonportions. or tip of sufliciently, hard material; such; as cemented tungstencarbides, torwithstands rapid wear. from brasion. Ithas. be n; eilstomary-. to braze; the cemented carbide tips to the upper. portionnoiithe work rest; which-is, generally: of steel. Because of. the difierenpes in: coefficients; of thermal; ex: pansion of cementedicarbide andsteel; trouble has-.beenencountered. in; brazing the carbide tips. to steel; To partially. overcome thisttroublethe carbide. tips. have beenv generally limited to a maximum length of: approximately two inches. Work rests, however-, are often-of a 2,4:inch1ength or more andit is,- therefore, neoessar'ysto: braze a number of these/tips to thebladei Also, fur-.. ther trouble is experienced as a result on the brazing operation that the finished blades warp into a bowed eonfiguration, necessitating a subsequenttr-uingoperation-- by expensive diarnond-eha-rg-edgrinding wheels with additional lossaccruing i-nview-0t the costly-carbide material that is removed during the grinding-operation.

Itis, therefore, another-object of the invention to provide a worl; restth-atmay-be readily manufacturedin a more economical:manner;

S iliamiher ob o fh nti m r ide an mnr vedf' esthar e; asii a t z y r e pper Sur ace- A iiirither. object. of" the, invention is to fuse carbide tips to a work; rest;v blade without subian iaflr Qi Qting the a isne r a h r f:

A still further object of the inventionis to prode a mmerse. r eraemen an thod f using. wo. m ter a s of, snb ian i dii ere i hermal oeiiq ems i rpa sioato eihen.

n E QG IQMJQQ' ith. one embodiment i. he inveaiioa mp or meots iih titre-are amed o warr or were. kw pr v d n he teel. other: m talii -bla ie o est wi h inr r ed-f E-shaneclznotehessnarede dinally alon t ie 1919 2: sa iaeeher oi and mg ti s, ofharden dmaterialcto, the blade tween the notches, while a substantial portion; i the. blade is preterahlyl disposed ina cooling. medium, th& .T-Sh&138dl-t notches being adapted: to reduce. thermal: conductivity irom the metallic body adjacent the heatedatipsto the mainporr- 2." tion. of; the b ade whereby bowins. he. b ad is snbstantianyrpr v nted-.1

This and; other: ieatu es; or; th invent n wil be mo e y descr bed iii-the iollonina 9 9i;- fication taken. in onnecti n-- wi h. the. hom: namin drawings'ninwhieha Fi i i-liustraies sqh mat ca i atypicalccnr. terless' grinding arran ement;

Fig. 211s a irontvievv q; tured. in. accordance with the: present in ton,

Fi 3 i a ectionaliv eiih tak n aloha. ne E41;-

of Eigt 6;

Elia 4. 1s. an end-.viewof th bladesh iri E s- 6; and

Pie. 5 is amendview of; a typi akwqrk. res -with angular: top. face.

R i rrinanow to the draw n partic lar y Fi i, thersis; shown sohe atieally. acente s rinder in wli h. a -w rlepieee; I01; i. ..d: p ed; be: tween asr ndinszwheel 1121a l4: and; upona Wprh rest in surface-1 l ry -a 1:85 i .QW ore dear in i 5a.- it: apparen ha dur cen er es r nding operations asthe. piece; Mt; rotates it carries with it particles of abrasive material f om; th rin in wh e l2. and: th se par icles tends-to wear. hetip l8. he worla e t. l6; t is; the fore hat: thet ps H! be mad of a hardened material to prevent rapid wear by ab asion. owever; as mentio ed; h re nheiore, there are om di ieo at s or n e da th raziaspem nted: carb de. tins: t e

cause orthe-difference betweentne coefiicients of thermal expansion of the two .;rn etals It isv this difference. whiohlimits the sizeofcarbide tipsnerality used toa. axim im e th. f; abou twoiuehes; lnasmuohasw rls 765125 1: cente less. grinders. are often. o en h. oi nches or-mora it. becomesineoess ry, Or e to mice tect; the entirelehsth, cause a number of ps bra d to. the d ef a work: 1 65. blade While the above procedure issatisiactory to a certain degree, it'has been. found that: the work; rest bladestend. to-warp. as; a result of the brazing. operation, whereupo v it is ne ves: sary totrue. the surface of: thetips. l8; by an expensive diamond grinding. operation. It. is readily apparent that further expense results from the Waste of the removed hardened tip material by the truing. operation.

Referring now tattle-drawings there is. shown an. improved work: rest 30: in which applicant has eliminatedathei aboveadescribed faults. Work rest 30 includes a plurality. of hardened tipsal, suoh ascemented tungsten. carbide, connected to a blade 32 in which the upper portion, such as a third thereof, is formed with a plurality of inverted T-notches or T-slots 33 comprising a narrow notch 34 and an elongated slot 35. This portion of the blade 32 is, therefore, divided into a plurality of T-shaped segments 36, which are spaced to correspond substantially with the length of the tips 3|, and are connected to the body of the blade by spaced necks 31. The blade 32 is further formed with V-shaped grooves 3'1 for receiving the complementarily-shaped tips 3|. Care is taken that the tips 3|, while bein brazed to the blade 32, will not be brazed to each other. Assurance of this is obtained by providing a slight space or gap between adjacent tips 3|. In order to prevent brazing material from reaching the ends of the carbide tips 3|, from where it would flow between the tips by capillary action, the bottom edges thereof are provided with chamfered corners 38 (Fig. 3) and the slots 34 between the segments 36 are made wide enough to allow any surplus brazin material to run off without bridging the gaps. In the embodiment shown in Figs. 2 and 4, the upper arcuate cross-section of the tip 3| was provided with a groove having a .252 radius. Occasionally, however, the tips are provided with an angular upper surface, as shown in Fig. 4.

During the brazing operation, the blade 32 is preferably first submerged in a cooling medium, such as water, to line A-A. Then the tips 3| are brazed in place one at a time, beginning at one end of the blade 32 and moving towards the other end. Since the solid bottom portion of the blade is kept cool, it will not expand. The T- shaped segments 36 are free to expand endwise and up without causing any trouble. The tips 3| cannot interfere with each other, because each tip, while being brazed, is in the maximum expanded condition. If a heated tip should touch a previously brazed tip, it will break contact after cooling, since the spacing from center to center of the segments 36 will not change, as the main portion of the blade is submerged in water.

It is thus readily seen that an improved and straight work rest may be economically manu factured in accordance with applicants invention.

While brazing torches have been referred to above as the source of heat for brazing, it is, of course, to be understood that other heating means may be used, such as high frequency in duction heating.

It is also to be understood that while the invention has been illustrated and described as especially useful in the attachment of cemented carbide tips to work rests, the invention may also be utilized in certain other applications where materials having different coefficients of thermal expansion must be fused together.

While this invention has been shown and described as embodying certain features merely for the purpose of illustration, it is, of course, understood that various modifications may be made in the details thereof without departing from the scope of the invention, as defined in the appended claims.

What is claimed is:

1. In a work rest, the combination with a plurality of hardened tip elements of a blade having a plurality of spaced segments along one edge thereof, said tip elements being respectively fused to said blade segments.

2. In a work rest, the combination with a plu- 4 rality of hardened tip elements of a blade having a plurality of spaced T-shaped segments along one edge thereof, said tip elements being respectively fused to said blade segments.

3. A work rest comprising, in combination, a blade and a plurality of hardened tip elements having a coeificient of thermal expansion substantially different from that of the blade brazed to said blade, said blade having spaced inverted T-notches adjacent said elements for reducing thermal conductivity at the joints formed between the tip elements and the blade.

4. A work rest for use in centerless grinding machines comprising, in combination, a metallic blade provided with a plurality of inverted T-notches at one edge for reducing thermal conductivity, and a plurality of cemented carbide elements brazed to said edge, said elements having chamfers at their inner corners for preventing brazing material from entering between adjacent tip elements.

5. In a work rest adapted for supporting a work piece in a centerless grinding machine, the combination of a metallic body having a V- shaped groove extending along one edge thereof with a plurality of cemented carbide tips disposed in said groove and fused to said body, said blade also having a plurality of elongated apertures for reducin thermal conductivity of said blade and for permitting expansion and corn traction thereof.

6. In a work rest adapted for supporting a work piece in a centerless grinding machine, the combination of a metallic body having a V- shaped groove extending along one edge thereof with a plurality of tungsten carbide tips disposed in said groove and brazed to said body, said blade also having a plurality of elongated apertures and T-shaped segments for reducing thermal conductivity of said blade and for permitting expansion and contraction of said segments.

'7. A blade for a work rest having one edge thereof provided with at least a pair of inverted T-notches and a T-shaped segment formed therebetween for reducing thermal conductivity and for permitting temporary expansion of said segment.

8. The method of fusing a plurality of elements havin one coeificient of thermal expansion to a member having a substantially different coefiicient of expansion without distorting the surface of the fused assembly which consists in providing a plurality of spaced notches 55 of substantial depth along an edge of the member adjacent to the joints formed between adjacent elements so that said edge is connected to the body of said member by a plurality of spaced necks, and fusing the elements step by 60 step to said neck.

9. The method of fusing a plurality of hardened tip elements to a metallic blade without bowing the surface of the composite assembly which consists in providing a plurality of spaced 65 inverted T-slots along an edge of the blade adjacent to the joints formed between adjacent tip elements whereby said edge comprises separate sections connected to the body portion of the blade by spaced necks, and separately braz- 70 in the tip elements to said sections of the blade edge.

10. The method of manufacturing a composite work rest blade which consists in forming the body of the blade with a plurality of inverted 75 T-notches disposed along one edge thereof whereby said edge comprises Separate sections connected to the body portion of the blade by spaced necks, placing separate tungsten carbide tips on the spaced sections of said edge, maintaining the unnotched portion of the blade in a cooling medium, and brazing the tips to said sections of the blade edge.

11. In the process of forming a work rest, including a blade and a plurality of hardened tip elements, forming inverted T-notches at predetermined points along one edge of the blade whereby said edge comprises separate sections connected to the body portion of the blade by spaced necks, placing the tip elements on said edge of the blade so that the spaces between adjacent tip elements are at the notches, cooling the unnotched lower portion of said blade, and individually brazing the tip elements without fusing adjacent elements together.

12. In the process of forming a work rest, including a blade and a plurality of hardened tip elements, forming a transverse V-notch longi- REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,342,717 Lipps June 8, 1920 1,615,591 Mallory Jan. 25, 1927 1,691,061 Heim Nov. 13, 1928 1,837,344 Stauder Dec. 22, 1931 2,034,418 Plant Mar. 17, 1936 2,064,407 Bird Dec. 15, 1936 

